Radio receiving apparatus



July 4, 1939. T. SORENSON v RADIO RECEIVING APPARATUS Filed Dec. 1, 1936 2 Sheets-Shah 2 Patented July 4, 1939 PATENT OFFICE RADIO RECEIVING APPARATUS Thoyer Sorenson, Cleveland, Ohio, assignor of one-half to John Y. Socotch, Cleveland, Ohio Application December 1, 1936, Serial No. 113,651

1 Claim.

This invention relates to an improvement in may be mounted in or on a box-like structure 5,

tuning mechanism for radios, and more specifically to an improved tuning condenser with adjusting and indicating means therefor.

An object is to provide an improved tuning mechanism for radios by which the operation of identifying and tuning in a great number of broadcasting stations may be greatly simplified, and rendered extremely accurate, without recourse to a reference book.

A further object is to provide a radio tuning mechanism in which the operative setting of the tuning condenser is indicated to the operator in such fashion that station selection and tuning may be easily effected, by very young children,

as well as adults.

A further object is to provide an improved condenser and operating mechanism therefor by which the operator of the receiving apparatus can tune in any station by movement of a dial in either direction from a given setting of such dial.

A further object is to provide an improved coarse and line adjustment in connection with radio tuning apparatus.

Still another object is to provide a tuning dial system in which the different dials are arranged as best suited to the character of the information carried thereon and which arrangement is adapted to be mounted in the relatively confined space of a small radio cabinet without interfering with other necessary parts of the instrument.

Other objects and features of the invention will become apparent from the following description relating to the accompanying drawings, The drawings show preferred embodiments of the invention. The essential characteristics are summarized in the claims.

In the drawings, Figs. 1 and 2 are rear and front views, respectively, of the upper portions of a radio cabinet incorporating the invention in one form; Fig. 3 is a sectional view in a vertical plane taken as indicated by the line 3-3 on Fig. 2; Fig. 4 is an enlarged sectional view, corresponding to Fig. 3 of the dial and condenser operating mechanism according to Fig. 2; Fig. 5 is a sectional detail view, showing the preferred shape of condenser plates; Fig. 6 is a front elevation of the upper portion of a radio cabinet showing another form of the apparatus, and Fig. 7 is a sectional view thereof, as indicated by the line 'I-'l on Fig. 6.

Referring to Figs. 1, 2 and 3, the radio cabinet there shown has a front wall I, top and side walls 2 and 3, respectively, and a dividing partition or shelf 4, connecting the side walls. The back of the cabinet may be closed in any suitable manner, not shown. The receiving unit carried on the partition or shelf 4.

A tuning condenser, comprising sets of rotary plates 8 and stationary plates 9, is mounted on top of the box-like structure 5. This condenser unit may comprise a base l0, on which the stationary plates are mounted, the base having upstanding arms or brackets I2 and I3, which carry a suitable supporting shaft I4 for the rotary plates, in substantially friction-free bearings, such as indicated at I5 and I6.

As shown in Fig. 5, it will be noted that the rotary plates 8 have portions of their edges at 60 which clear the plates 9 in one setting of the rotary plate unit, and that the stationary plates overlap the rotary plates in generally V-shape by reason of the corner portions of the plates which come to a point at BI, the point being directed generally toward the rotational axis of the rotary unit. One edge 62 of each stationary plate may be straight and directed toward the axis of the shaft I4 and the other active edges 63 of the plates may form substantially right angles with the edges 62, the edges 63 being slightly curved so that the point BI is less than a right angle. The rotary plates in the full capacity tuning position (shown in Fig. 5) have their farthest outlying portions 64 in maximum overlapping relation to the fixed plates. Now by a short turn of the rotary unit (about 60 counterclockwise, the pointed portions of the plates 9 may be brought into minimum capacity position with respect to the rotary plates, or by turning the unit clockwise the capacity may be gradually reduced to the minimum. Due to the rate of decrease of overlapping areas provided by the spiral shape of the rotary plates and the described shape of the fixed plates, the capacity variations from full to minimum can be noted on a dial by equal divisions.

An inset portion of the front wall of the cabinet is formed by an illuminated dial I8, having a casing I9 behind it for suitable lights, such as electric bulbs L. The supporting shaft I4 for the rotary plates .of the condenser may extend through the dial as shown in Fig. 3. The projecting end of the shaft supports an indicat ing hand or pointer 20. This pointer, as shown in Fig. 2, terminates over or near circumferentially spaced graduations 2|, indicating, for example, the kilocycle ratings of standard broadcasting stations. A portion of the dial swept by the pointer 20 may be suitably graduated, as at 22, for short-wave reception, concentrically with the standard broadcasting graduations 2I. Thus, the same tuning dial is used in the standard and short-wave settings of a knob W (Fig. 2) on the face of the cabinet.

The rotor and stator plates, the preferred shapes of which are illustrated in Fig. 5, are

the drum 40.

highest capacity indications have been reached.

Indications by the pointer 20 are necessarily limited to relatively coarse adjustment, since the pointer 20 moves with the rotary condenser,

plates 8. Cooperating with the coarse adjustment indicator, I provide a Vernier or fine adjustment indicator in the form of a hand or pointer 25, supported on a sleeve 26 surrounding the outwardly projecting end of the shaft I l, and which is geared downwardly from the shaft, but in such manner as to turn in timed relationship therewith.

The Vernier adjustment connections comprise, as shown in Figs. 3 and 4, a system of reduction gearing, including gears 27 and 28, on the shaft l4 and sleeve 26 respectively, these gears being in constant mesh with inter-connected gears 29 and 35, respectively. The latter gears may be carried on a jack-shaft mounted on the bracket I3, in parallel relation to the shaft M. The sleeve 26, as shown, is connected by a driving belt 3|, passing over pulleys secured respectively to the sleeve 26 and a shaft 33. The latter shaft may be supported in any convenient manner, as on the front wall of the cabinet, and extending outwardly therefrom. The outer end of the shaft carries a knob 34, which may be adjusted by the fingers of the operator in the usual manner of operating a tuning knob, or the knob may be spun by means of a swivelled crank piece 35 journalled in antifriction bearings 36 in the knob, eccentrically of its axis. The member 35 has a depression on its outer face to receive the end of such finger. Because of the free mounting of said member in the knob it is a simple matter to spin the knob very rapidly with the index finger. The geared relationship between the shaft l 4 and the sleeve 26 may be such that the hand or pointer 25 makes one complete rotation for each one-twelfth of a rotation on part of the hand or pointer 20. Accordingly, the graduations which are associated with the ends of the pointer 25 may be divided into minutes, the same as a clock face, as indicated at 3-1 on Fig. 2.

The coarse and fine indicating portions of the dial already described, or a single set of indications, if those are the only ones present, (as shown in Fig. 6, see hand 50), may be supplemented by indications on a drum 40, suitably mounted inside the cabinet, and viewable through an elongated narrow window 41 in the front wall of the cabinet. Such drum may be mounted on bracket members 4| rising from the end walls of the box construction 5 and supported thereon.

The drum 4!] may be arranged to be driven in one to one ratio with the rotary condenser plates by means of a flexible member, such as a chain 43, having one loop engaging a sprocket wheel 44 attached to the shaft l4 and the other loop engaging a sprocket wheel 45 drivingly rigid with Since the drum shaft and condenser plate shafts are at right angles to each other, the chain may be guided for proper coaction with the sprockets by means of idlers 46, so disposed that the surfaces which contact with the chain stretches are in trasverse alignment with both sprockets. Any convenient bracket arrangement, carried as on the box'structure 5, may be provided to support'the idlers.

The drum, by reason of its amplified surface, may carry much more information than can a flat dial with revoluble pointers. Three or more station identifications, as shown in Fig. 2, at 40a, 40b and 400, may occupy a single line viewable simultaneously through the window 41. Such stations would not, of course, have the same wave length. Hence, each station may have suitable indicia' correlated with symbols on the dial l8 to assist in tuning in the various stations listed in each'line. Suppose the listing at40areads WRB Denver Q32. This indicates the proper position for the pointer 25 (adjacent the marking Q on the dial l8) and also the position of the Vernier pointer 25 (adjacent graduation 32 on the vernier dial). In order to tune in the other two stations in line with Denver the Vernier pointer would be shifted to 34 and 33 of the graduations at 31. ous stationsmay also be indicated on the drum.

In Figs. 6 and '7 the main dial arrangement is simplified by providing but one pointer, 50. Such pointer may be directly connected to the shaft which carries the rotary condenser plate 8, or

connected thereto by gearing, such as already described. The condenser plate supporting shaft is shown in Fig. 7 as connected directly with the drum 40 by means of a flexible shaft 52, so that the drum turns intimed relation to the shaft (one-to-one ratio as shown). Such connection is somewhat simpler than the chain drive, heretoforedescribed, and less likely to get out of order.

It will bezseen' that the apparatus provides adequate space for indicating the necessary data in regard to a great number of broadcasting stations. Moreover, reading of the dials is rendered extremely simple and :no log or reference book is required to locate remote or unusual stations. Moreover, tuning can be accomplished with utmost fineness and without loss of time. It is a very simple matter to move the rotary condenser plates rapidly throughout an entire rotation by means of spinning the knob, using the swivelled finger-piece 35, and when the approximate location of the station is reached on the dial, then fine tuning can be effected by turning the knob manually with the fingers. Moreover, the entire apparatus can be located within the small space of a standard household 5:

radio cabinet.

I claim: In a radio receiving set, a housing having an condenser also supported within the housing and including a rotating member disposed out of the plane of the drum axis, a positive driving connection between the drum and-the rearward, end of the rotating tuning member, the forward end of the rotating tuning member having a portion thereof projecting through the housing and having a pointer thereon, a manually operable member, and means for operatively connecting,

the manually operable member to the rotating tuning member:

I TI-IOYER soRENsoN.

The kilocycle ratings of the vari- 

